The present invention relates to heating device to be adhered through a soft solder or a hard solder material layer to a heated body to supply heat thereto, and more particularly relates to the construction of a heating section of the heating device.
A heating device using a high melting point metal film resistance heater is disclosed in Japanese Patent Application Laid-Open Hei-9-322901 as for cautery hemostasis device to be used as an endoscopic treatment tool. FIGS. 1 and 2 are a perspective view and a side sectional view, respectively, showing a heating section of the heating device as disclosed in the above publication with omitting a portion thereof to indicate its interior. FIG. 3 is a sectional view along line A–A′ in FIG. 1. FIG. 4 is a side view showing the heating section of the heating device in its state joined to a heated body.
In the heating device disclosed in the above publication as shown in FIGS. 1 and 2, an electrically insulating material, preferably an electrically insulating layer 102 having a thickness of 0.3 μm to 100 μm made of high-molecular material such as silicon dioxide or polyimide is formed on and adhered to one main surface of a heating device substrate 101 having a thickness of 0.2 mm to 3.0 mm made of a semiconductor or silicon dioxide or ceramics. The electrically insulating layer 102 serving as an insulating member becomes unnecessary when the heating device substrate 101 is dielectric.
As shown in FIG. 3, a heating layer 103 made of a high melting point metal film having a thickness of 0.1 μm to 50 μm for example of patterned titanium, molybdenum or tungsten or of an alloy film of such high melting point metals is formed on and adhered to the electrically insulating layer 102. A portion to be heated of the heating layer 103 is narrowed to a line width of 0.1 μm to 100 μm to provide high resistance so as to facilitate its localized heat generation. A wiring layer 104 having a thickness of 0.1 μm to 50 μm of a low resistance metal film for example of patterned aluminum or copper or of an alloy film of such low resistance metals is formed on and adhered to the heating layer 103 and electrically insulating layer 102, and a contacting portion between the heating layer 103 and the wiring layer 104 is electrically connected. The reason for providing the wiring layer 104 is to prevent heat generation due to electric conduction at a center portion of the heating device substrate 101.
A heat conducting and electrically insulating layer 105 having a thickness of 0.3 μm to 50 μm of a material such as aluminum nitride or aluminum oxide having a relatively high thermal conductivity as an electrically insulating material is formed on and adhered to the portion to be heated on the heating layer 103. Then an electrically insulating layer 106 having a thickness of 0.3 μm to 100 μm is formed on and adhered to an edge portion 105a of the heat conducting and electrically insulating layer 105, and the wiring layer 104 and electrically insulating layer 102.
In the case where a high-temperature resisting solder is used as the adhering technique of the heated body to the heating device, a solder connecting layer 107 using a metal material such as nickel is provided on the heat conducting and electrically insulating layer 105 to secure adhesion of the solder. Here a metal material such as nickel is to be simply used as the heating device side solder connecting layer 107.
As shown in FIG. 4, an adhering layer 109 of a material such as a high-temperature resisting solder or an adhesive that resists high temperatures and has a favorable thermal conductivity is provided between the heated body 108 and the solder connecting layer 107 to facilitate heat conduction from the heating section of the heating device to the heated body 108.